This proposal is a revision to the previous application l Rl3 HD31825-01, and is a request for funds to organize a meeting on Hirschsprung disease and related neurocristopathies, primarily from a genetics and developmental biology perspective. This meeting will be held at the Case Western University School of Medicine during October 21-23, 1995. We expect to attract a minimum of 100 scientists, and request funds to support the travel and subsistence costs of 15 US and 15 foreign investigators. The conference will aim to review, discuss and synthesize current research on Hirschsprung disease and related neurocristopathies, including Waardenburg syndrome, Down syndrome, Multiple Endocrine Neoplasia II and related phenotypes (medullary thyroid carcinoma, pheochromocytoma) and Congenital Central Hypoventilation syndrome, in the human and in animal models. A particular emphasis would be placed on understanding the relationships between the clinical phenotype in HSCR and the emerging biology of the neural crest and the enteric nervous system. The primary objectives of the conference would be to: (l) present a thorough overview of the genetics, developmental biology and clinical genetics of HSCR and related neurocristopathies; (2) develop an understanding of the relationships between the clinical and pathophysiological phenotypes of HSCR and related disorders in terms of the known genes and their mutations; (3) stimulate thinking and discussion of novel and existing strategies and approaches for answering the many outstanding basic and applied biological questions; the two most general questions are, how does the enteric nervous system develop and how does HSCR or other neurocristopathies develop?; (4) enable the sharing of data and ideas, and fixture cooperative research efforts.